Static analysis tools find defects in code, checking code against rules to reveal potential defects. Many studies have evaluated these tools by measuring their ability to detect known defects in code. But these studies measure the current state of tools rather than their future potential to find more defects. To investigate the prospects for tools to find more defects, we conducted a study where we formulated each issue raised by a code reviewer as a violation of a rule, which we then compared to what static analysis tools might potentially check. We first gathered a corpus of 1323 defects found through code review. Through a qualitative analysis process, for each defect we identified a violated rule and the type of Static Analysis Tool (SAT) which might check this rule. We found that SATs might, in principle, be used to detect as many as 76% of code review defects, considerably more than current tools have been demonstrated to successfully detect. Among a variety of types of SATs, Style Checkers and AST Pattern Checkers had the broadest coverage of defects, each with the potential to detect 25% of all code review defects. We found that static analysis tools might be able to detect more code review defects by better supporting the creation of project-specific rules. We also investigated the characteristics of code review defects not detectable by traditional static analysis techniques, which to detect might require tools which simulate human judgements about code.